In recent years, a form for applying, as a network infrastructure for various kinds of automatic metering for electricity, water service, and gas, ad hoc communication in which a plurality of communication units communicate with one another by radio and multi-hop to form a wide area network has been examined. By using the ad hoc communication, it is possible to realize an automatic metering system that covers a wide range area while suppressing facility costs (see Non Patent Literature 1)
In route establishment in the ad hoc communication, a network is built by exchanging route information among radio communication terminals (the communication units). A plurality of systems for means for exchanging the route information and the route establishment (a routing protocol) are examined and standardized by an IETF (Internet Engineering Task Force) (see Non Patent Literatures 2 and 3).
In the automatic metering system, a job application for performing collecting of meter reading data and monitoring and control of the network is operated through the ad hoc communication network infrastructure. However, it is unrealistic from the viewpoints of the number of multi-hops and collection traffic to provide the network infrastructure from the communication unit to a job server (a server that collects meter reading data) in a data center through the ad hoc communication of the same radio media. Therefore, a system model is assumed in which distributedly-arranged gateways, which relay the ad hoc communication network and an existing IP network, perform communication medium conversion and protocol conversion to thereby enable communication between the job server and the communication units.